Fabric treatment



June 21, 1966 Original Filed April 5, 1963 L. E. MOULTHROP FABRICTREATMENT 2 Sheets-Sheet 1 INVENTOR. LEROY E. MOULTHROP ROBERT J PATCH ATTORNE Y June 21, 1966 L. E. MOULTHROP 3,256,613

FABRIC TREATMENT Original Filed April 5, 1963 2 Sheets-Sheet 2 F|G 2TIME-MINUTES 3 4 5 6 7 8 9 IO II I2 I3 I4 I5 TIMER MOTOR FILTER PUMPMOTOR 27 EDUCTOR PUMP MOTOR 89 WASH MOTOR I5 VAPOR REMOVAL VALVE 55 FANIO7 BY-PASS VALVE 39 FILL VALVE 3| DUMP VALVE 47 VACUUM BREAK VALVE 5IEXTRACT MOTOR l7 VAPOR RECYCLE VALVE II5 HEATER III WASH EXTRACT RECLAIMFIG.. 3

TIME MINUTES OI23456789IOIII2IEII4I5 PRESSURE INCHES OF MERCURY '6INVENTOR. E. MOULTH ROP ROBERT J. PATCH ATTORNEY United States Patent3,256,613 FABRIC TREATMENT Le Roy E. Moulthrop, Alhambra, Calif,assignor of twenty-five percent to Robert J. Patch, Chevy Chase, Md.Uriginal application Apr. 5, 1363, Ser. No. 270,832, new Patent No.3,110,544, dated Nov. 12, 1963. Divided and this application Nov. 12,1963, Ser. No. 345,829

12 Claims. (Cl. 34-15) This application is a division of copendingapplication Serial No. 270,832, filed April 5, 1963, now Patent No.3,110,544, November 12, 1963.

The present invention relates to cleaning methods for removing dirt suchas grease, grime or stains or the like from fabric by contact with acleaning liquid. The fabrics thus treated are comprised of animal,vegetable or certain synthetic fibers or the like, and may for examplebe woven, knitted, felted, and so on. The principal field of applicationof this invention is in the cleaning of wearing apparel.

The invention will be particularly described and illustrated inconnection with dry cleaning by the use of organic liquids of the typeof perchlorethylene, 1,1,2-trichloro-l,2, 2,-trifluoroethane (Freon113), Stoddard solvent and other petroleum fraction solvents,trichlorethylene, carbon tetrachloride, and the like. It is to beexpressly understood, however, that the invention in many of its aspectsis not limited to dry cleaning but rather is applicable also to waterwashing, and that the term cleaning includes washing both with organiccleaning liquids and with inorganic cleaning liquids such as water.Similarly, the term cleaning liquid includes both organic and inorganiccleaning liquids and includes water.

The prior art cleaning methods are deficient in that they provide nosatisfactory methods for drying the fabric after cleaning, and in thecase of dry cleaning, no satisfactory methods for reclaiming the drycleaning solvent. In the first place, the drying methods of the priorart are so slow that they must be practiced in separate dryers ortumblers so that the washing equipment will not be unduly tied up duringthe long and slow drying process. As a result, it has been necessary toprovide, in addition to the machines designed to wash and spin thefabric until it is damp dry, separate dryers or reclaimers so that aneconomically large quantity of fabric can be handled in the generallymore expensive washing and extracting apparatus. But the multiplicationof the numbers of pieces of equipment thus necessary not only increasesthe capital investment of the professional cleaner but .also ties upexpensive fioor space and necessitates a larger plant. Also, in the caseof highly odorous dry cleaning solvents, the transfer of the damp fabricfrom the washer-extractor to the dryer or tumbler causes a great deal ofmalodorous vapor to be thrown out into the plant, and this in turnnecessitates installation of larger capacity ventilating equipment forthe plant.

In addition to their inability to dry fabric quickly, the cleaningsystems of the prior art have also suffered from the disadvantage thatthey damage fabric by over-heating it during drying or reclamation. Inthe case of all types of cleaning, excessive temperature during dryingof the fabric can damage the fabric by charring and in other ways; andin particular, in the case of dry cleaning with organic solvents,excessive temperature can decompose and carbonize the solvent withresultant damage not only to the fabric but also to the equipment, andin the case of halogenated hydrocarbon solvents, can give rise to theproduction of such poisonous gases as phosgene and/ or hydrogenfluoride.

Accordingly, still another object of the present invention is theprovision of cleaning methods which will be 3,256,6l3 Patented June 21,1966 ice so fast that they can be economically practiced in a singlepiece of equipment having a dry-to-dry cycle time that is shorter thanany known heretofore under comparable circumstances.

The invention also contemplates the provision of cleaning methodscharacterized in that drying or reclamation can be carried out at atemperature low enough to avoid damage to the fabric, and in the case ofdry cleaning, to avoid damage to the equipment and the production ofnoxious decomposition products of the solvent.

In the particular field of dry cleaning, in which the cost of thesolvent makes it necessary to reuse the solvent, it is necessary topurify the solvent from time to time by passing it through a porous bodyof solid material in the nature of filtration and/ or adsorption means.Most commonly, these means for cleaning the solvent employ a finelydivided solid material as a principal constituent of the porous body, inthe-nature of filter powder which may be supported on a foraminoussupport that permits the passage of liquid through the support but notthe pass-age of the filter powder. Filter powder for example may bediatomaceous earth or silica or the like, or, depending on the nature ofthe impurity to be removed from the solvent, charcoal. In any event, thefinely divided material of the porous body of solid material from timeto time becomes so highly charged with removed impurity that it must beremoved and discarded and a fresh quantity of finely divided materialadded to the system. However, the spent material, or muck as it is knownin this art, contains a large quantity of solvent, which must bereclaimed it the cleaning operation is to be conducted economically. Inthe past, it has been the practice to clean out the muck and put it in acooker which heats the muck to the point that the solvent is distilledoff. The vapor phase solvent distilled off the muck is then condensedwith refrigeration and reused. Such a procedure, however, has thedisadvantages that it requires special equipment and consumes asubstantial quantity of power. Also, the transfer of muck to the cookeris a messy and disagreeable job. Furthermore, recovery of the solvent byuse of a cooker is a long and time-consuming process.

Therefore, a further object of the present invention is the provision ofdry cleaning methods characterized by simple, easy, rapid and economicalreclamation of solvent from muck,

Finally, it is an object of the present invention to pro.-

vide cleaning methods that will be relatively simple, fast andinexpensive to practice, and that are well-adapted to be practiced byapparatus that is desirably compact in size, inexpensive to manufacture,easy to operate, and rugged and durable in use.

Other objects and advantages of the present invention will becomeapparent from a consideration of the following description, taken inconnection with the accompanying drawings, in which:

FIGURE 1 is a diagrammatic view of a cleaning system according to thepresent invention;

FIGURE 2 is :a time sequence chart showing one embodiment of a cycle ofoperation of the present invention; and

FIGURE 3 is .a graph of pressure against time, showing the pressurevariations to which the fabric under treatment is subjected during acleaning cycle of the present invention according to the embodiment ofFIGURE 2.

A very important feature of the invention is the drying portion of thecycle which is carried out first by heating the fabric and then bydrawing a deep vacuum on it. The principalportion of the reclamationcycle follows immediately on the extraction-cycle, and is characterizedby a relatively slow tumbling of the fabric in the chamber. Hot vapors,preferably laden with vapors of cleaning liquid, are circulated throughthe fabric to raise the fabric a to arr elevated temperature.Thereafter, a deep vacuum is drawn on the heated wet fabric, and theremaining liquid in the fabric is quickly boiled off, leaving the fabricquite dry but not too hot to be comfortably removed from the machine byhand.

The drying or reclamation process of the present invention is not beconfused with drying processes in which vacuum is continuously pulledduring drying and heat is continuously simultaneously applied to fabric.In such prior art drying or reclamation processes, it is necessary toapply the heat directly to the fabric, as by heating elements in contactwith the fabric, in order to supply the necessary heat to the fabric. Bycontrast, in the present invention, in which the fabric is heated bycirculation of hot vapors prior to drawing the deep vacuum, it ispossible to apply as much heat as is desired to the fabric in theshortest possible time, by increasing the flow rate and/ or heat contentof the hot circulating vapors, thereby to heat the fabric in the minimumtime. For this purpose, the heating elements are disposed outside thechamber. When it is attempted simultaneously to heat-the fabric and drawvacuum, however, or alternately to heat the fabric and draw vacuum in aplurality of repeating cycles, it is found that the heating must beperformed quite slowly so as to avoid charring the fabric or carbonizingthe cleaning liquid because the heat must be applied directly to thefabric by the heating elements.

Thus, an important feature of the drying or reclamation process of thepresent invention is that the heat content of the fabric and itscontained liquid at the higher temperature and pressure is at leastabout as great as the heat content of the fabric at the lowertemperature and pressureto which it falls upon drawing the deep vacuum,plus the total heat of vaporization of the contained solvent at thatlower temperature and pressure.

Another very important feature of the present invention is the way inwhich this vacuum is achieved and maintained. The kinetic energy of arelatively high pressure stream of liquid is used to withdraw arelatively low pressure stream of vapor from the cleaning chamber. Thisliquid is the same cleaning liquid that is used in the wash cycle. Abody of cleaning liquid is maintained, and the relatively high pressurestream of liquid, with its entrained relatively low pressure stream ofvapor, is directed beneath the surface of this body of liquid.Preferably, the vacuum-producing device is in the form of an eductorwith the high pressure stream of liquid supplied from the body of liquidand the outlet of the eductor directed to a point below the surface ofthe body of liquid. Preferably, at least the outlet of the eductor issubmerged in the body of cleaning liquid. This method of vacuumproduction is especially desirable in connection with the recovery ofdry cleaning solvent vapors, because the vapors are partially condensedas they enter the low pressure inlet of the eductor and contact thehigher pressure liquid stream, and are still further condensed when theyemerge from the eductor and bubble up through the body of dry cleaningsolvent.

In the case of dry cleaning, a further feature of the invention inconnection with the production of vacuum is that the vapors withdrawnfrom the cleaning chamber under vacuum are partially condensed to theextent necessary to condense substantially all the water in the vaporsand a portion of the dry cleaning solvent. The remaining vapors, and thecondensed water and the condensed solvent, are then gravity separated ina phase separator, with the uncondensed vapor going to the low pressureinlet of the eductor, the water being discarded and the dry cleaningsolvent being returned to the collected body of solvent. It has beenfound that in this way, the formation of wrinkles in the fabric in thecourse of the dry cleaning process can be entirely avoided.

Still another feature of the present invention in connection with drycleaning is the provision of a closed circuit refrigeration cycle,characterized in that a refrigerant moves in a closed cycle alternatelythrough compression and expansion, with the heated refrigerant followingcompression being used to heat vapors that are introduced into thecleaning chamber to heat the fabric, and the cooled refrigerantfollowing expansion being used in the partial condensation of vaporsfrom the cleaning chamber, referred to immediately above, and also tocondense excess vapors vented from storage. The refrigerant followingexpansion is also used to refrigerate the collected body of dry cleaningsolvent.

Finally, the invention is characterized by an easy method of recoveringdry cleaning solvent from the muck, comprising backwashing the filter,that is, running liquid through the filter and/or adsorber units in thereverse of the normal direction so as to dislodge finely divided filteraid and/or adsorbent from the solvent cleaning equipment, followed by avacuum reclamation of the muck thus dislodged. Preferably, the muck fromwhich the solvent is to be reclaimed is placed in vacuum communicationwith the low pressure inlet of the eductor, so that no application oflarge quantities of extraneous heat is necessary to remove and recoverthe solvent from the muck in a short period of time.

One of the many embodiments of appartus by which the present inventionmay be practiced is shown schematically in FIGURE 1. The entireoperation of the apparatus of FIGURE 1 including washing, extracting andreclaiming, is conducted in a closed cleaning chamber 9 which is apressure-type vessel having a closure comprising a door (not shown).Preferably, the vessel is cylindrical for added strength under pressure.Cleaning chamber 9 contains a rotatable basket or cylinder 11, the outercylindrical periphery of which is multiperforate. Chamber 9 and cylinder11 are coaxial about a horizontal axis. Cylinder 11 rotate on its axisrelative to stationary chamber 9 and contains a plurality of inwardlyextending batlies 13 on the inner side of its cylindrical periphery, forthe purpose of agitating the fabric and the cleaning liquid as thecylinder turns.

Means are provided for turning the cylinder at variable speeds,comprising a wash motor 15 which rotates the cylinder at a relativelylow speed of rotation, for example 40 r.p.m., and an extract motor 17that rotates the cylinder at a relatively high speed of rotation, forexample, 625 r.p.m. Motor 15 operates during washing and drying, whilemotor 17 operates during spin drying or extraction.

In the case of a dry cleaning operation, a closed and hermeticallysealed tank 19 is provided that serves to store 'a body of dry cleaningsolvent 21. As used herein, the term body may include several separatesub-bodies of solvent maintained under different temperatures and/ orpressures. Solvent 21 is withdrawn from the bottom of the supply througha supply conduit 23 and passes through a filter and/or adsorber unitindicated at 25, on its way to the cleaning chamber. The solventcleaning means indicated generally at 25 can of course take the form ofplural units containing different porous solids for cleaning the liquidand preferably includes finely divided solid material in the form offilter aids or adsorbents or the like, as discussed above. However, forthe sake of brevity, the solvent cleaning system will hereafter bereferred to as filter 25, it being understood that this term may referto a plurality of different units including adsorption units.

A filter pump 27 in conduit 23 urges solvent toward filter 25 under thecontrol of a valve 29. Downstream of filter 25, a fill valve 31regulates the flow of solvent into the cleaning chamber. A conduit 33 isprovided, under control of a valve 35, that permits the flow of solventpast filter 25. A bypass conduit 37 also permits the flow of solventfrom filter 25 back to tank 19. Conduit 37 is controlled by by-passvalve 39. A conduit 41 controlled by a valve 43 permits the flow ofsolvent back to tank 19 without going through filter 25. Ac-

cordingly, liquid from tank 19 may be sent either through filter 25 andinto chamber 9, or through filter Z5 and back to tank 19, or past filter25 into chamber 9, or past filter 25 and back to tank 19, or alongseveral other paths, as will be apparent from FIGURE 1.

Liquid in chamber 9 can drain by gravity through 'a dump conduit 15under control of a dump valve 4-7,

back into tank 19. To permit the pressure in chamber 9' to rise towardatmospheric, a vacuum break conduit 19 is provided that lets air intochamber 9 under control of vacuum break valve 51.

To remove vapor from th chamber so as to create a vacuum in chamber 9and/ or to dry the fabric, a vapor removal conduit 53 is provided thatcommunicates with a peripheral portion of chamber 9 outside cylinder 11.A pair of vapor removal valves 55 and 57 are provided in conduit 53 inparallel to each other. Valve 55 is operable between fully opened andfully closed positions, while valve 57 is more in the nature of a bleedValve that can be set for a continuous, rather restricted flow of vaportherethrough.

The vapor leaving chamber 9 through conduit 53 passes through acondenser 59 in which it is partially condensed to the extent needed tocondense substantially all of the water and a substantial proportion ofthe solvent in the vapor. Even if the solvent boils higher than water,-as in the case of perchlorethylene, substantially all of the water canbe condensed while only partially condensing the perchlorethylene,because the quantity of water in the vapor in conduit 53 from a drycleaning operation will be only a small fraction of the quantity ofsolvent in the vapor.

The partially condensed mixture enters a phase separator 61, from whichuncondensed vapor phase material containing at least a substantialproportion of vapors of solvent is removed through an overhead conduit63. The condensed water and solvent will accumulate in two layers in thebottom of the phase separator, because they have different densities andar immiscible. In the case of a solvent such as perchlorethylene, whichis substantially heavier than water, there Will be an upper layer 65 ofwater which may be removed through a conduit 67 and sewered, and a lowerlayer 69 of solvent which can be removed through conduit 71 past checkvalve 73, past control valve 75 and returned to tank 19. Phase separator61 is of course shown only very schematically. It will be understoodthat it can take any of the usual forms for separating unmixed liquidsby gravity, such as by means of a float that will sink in water andfloat in perchlorethylene and which regulates the operation of controlvalv 75, closing valve 75 at a lower position of the float and openingvalve 75 at an upper position of the float, in combination with a liquidoverflow for water into conduit 67.

Vapor is moved through the system by means of an eductor 77 submerged intank 19. Eductor 77 has a high pressure inlet 79 and a low pressureinlet 81, a stream of liquid under relatively high pressure passingthrough the high pressure inlet serving to draw in a stream ofrelatively low pressure fluid through the low pressure inlet 81. Themixed stream then passes through a reduced throat 83 and emerges from anoutlet 85 beneath the surface of and in contact with solvent 21. Aneductor pump 87 draws liquid from beneath the surface of solvent 21 intank 19 and forces it through high pressure inlet 79 at elevatedpressure and at a substantial velocity as the high pressure stream. Amotor 89 is mounted on a removable cover 91 on tank 19 and has its driveshaft 93 extending vertically down to pump 87 to drive pump 87. Conduit63 also passes downwardly through cover 91 to the low pressur inlet ofeductor 77. A coupling 95 in conduit 63 permits the portion of conduit63 secured to cover 91 to be detached from the rest of conduit 63, sothat cover 91 with motor 89 and shaft 93 and pump 37 and eductor 77 canbe removedas a unit from the top of g. the tank without the need fordraining the solvent from the tank. Detachable fastenings 97 remova blysecure cover 91 in hermetically sealed relationship with tank 19. Tank19 is thus entirely sealed except for the entrance and exit conduits forliquid and vapor and drive shaft 93.

A vent conduit 99 provides egress for vapors in tank 19 above body ofsolvent 21. The vapors pass through a condenser 1111 in whichsubstantially all of the solvent vapors are condensed and fall*backwardly into tank 19 in liquid phase. A check valve in the form of abutterfly valve 103 ensures that vapor. can move only one way throughconduit 99, and is especially usefulin climates characterized by highhumidity, so that the quantity of water added to the system will be keptto a minimum.

A vapor recycle conduit 105 is also provided, for removing vapors fromchamber 9 from the outer side of cylinder 11, heating the vapors, andreturning them to the interior of the chamber within cylinder 11. Afilter 10:: catches and removes solid particles of dirt and lint fromthe vapor circulating in conduit 195. To facilitate circulation of thevapors, a fan 107 is provided in conduit 1115. Heaters 109 and 111 arealso traversed in series by the vapors in conduit 1115. Heater 109operates at a lower temperature level and heater 111 operates at ahigher temperature level. Heater 111 is heated by a heating coil 113,which preferably is supplied with steam from a boiler. A vapor recyclevalve 115 in a conduit 117 controllably connects'conduit 1115 with ventconduit 99 so that vapors free from water can be added ot the vaporrecycling in conduit 105. Of course, instead of connecting conduit 117to conduit 99 downstream of condenser 101, it is also possible toconnect conduit 117 directly with the vapor space in tank 19.

A closed cycle refrigeration circuit 119 is also provided, comprisingthe usual compressor 121 and' expansion valve 123. However, therefrigeration circuit of the present invention diifers from thoseheretofore known in this art in that relatively warm vapor followingcompression in compressor 121 is utilized in a heating coil 125 thatprovides heat for heater 109. Heating coil 125 is thus downstream ofcompressor 121 and upstream of expansion valve 123. Cooling coils 127'and 129 are provided in condensers 59 and 1111, respectively, and afurther cooling coil 131 is submerged in the solvent 21 in tank 19 so asto maintain the solvent temperature at a desirably low level, e.g., notmore than about 70 F. or lower depending on the nature of the solvent.Cooling coils 127, 129, and 131 are shown in parallel with each other;but of course it will be realized that they can be in series or in otherarrangements, depending upon the desired refrigeration duty to be borneby them. In any event, cooling coils 127, 129, and 131 are downstream ofexpansion valve 123 and upstream of compressor 121 in circuit 119. Ofcourse, the temperature level of re frigeration circuit 119 may beadjusted upwardly or downwardly as desired. For example, an air cooler(not shown) for the refrigerant can be provided downstream of heatingcoil 125 and upstream of expansion valve 123. The refrigerant itself maybe any of the usual refrigerants, such as ammonia or the halogenatedhydrocarbons,

e.g., chlorodifluoromethane (Freon 22).

For reclaiming solvent from spent muck from filter 25, a filter backwashconduit 133 is provided under the control of a valve 135. Conduit 1333delivers into a muck reclaimer 137 characterized. by a tube sheet 139provided with a plurality of openings in each of which is set amultiperforate tubeor screen tube 141, so that backwashed muck can enterreclaimer 137 above tube sheet 139 and its liquid drain and be drawnthrough tubes 14.1 and out through a conduit 143 controlled by a valve145, that communicates with conduit 63, so that the vacuum in conduit 63induced by eductor 77 also pulls on muck reclaimer 137 when valve isclosed.

A dry cleaning cycle according to the present invenvention will now bedescribed in connection with the cycle diagram and pressure diagram ofFIGURES 2 and 3. It is of course to be understood that the followingcycle is merely one of many that can be devised to carry out theprinciples of the present invention. It is also to be understood thatthe pressures indicated on FIGURE 3 are only generally representative ofwhat goes on in the cleaning chamber. It should be noted, however, thatFIGURES 2 and 3 are in vertical alignment with each other, so that theevents depicted in FIGURE 2 correspond to the pressures indicateddirectly below them in FIGURE 3. It should further be noted at theoutset that the total cycle time, dry-to-dry, is only minutes, which isincredibly short for a commercial dry cleaning machine using a solventsuch as perchlorethylene. This cycle time is not merely illustrative butis one of the actual very short cycle times that have been achieved bythe practice of the present invention. In general, the short cycle timeis achieved by the unique cleaning methods, by certain novel stepsduring extraction, by the unique reclamation process of the presentinvention, and by so arranging the cycle that a number of the events inthe cycle overlap each other timewise. These various features of theinvention coact together to permit an extremely short overall cycle timefor the dry-to-dry process adapted to be carried out in a singlemachine.

Beginning at the left hand margin of FIGURE 8, therefore, it will beseen that as the cycle begins, the timer motor (not shown) is actuatedwhich may for example turn a cam shaft (not shown) through one fullrevolution during the cycle. The .cam shaft may carry a series ofgenerally circular cams (not shown) each of which corresponds to one ofthe timed elements of the present invention. Although the cycle of thepresent invention is novel in many respects, the mechanical operation ofthe timer motor and cam shaft, and the concept of timing the variouselements each by means of its individual cam on .the cam shaft, arequite conventional and hence need not be illustrated in the drawings.

The filter pump motor 27 is shown as being in op eration throughout thecycle. Of course, it will be understood that except when flow valve 31is open and solvent is being introduced into chamber 9, filter pumpmotor 27 may be operated or not as desired and as necessary to keep thesolvent clean. Thus, filter pump motor 27 may be operated during theentire cycle, or during only part of the cycle, and during periods ofoperation that fall between cycles.

The eductor pump motor 89 operates throughout the cycle and a vacuum isconstantly being drawn on conduit 63 by eductor 77. Even when vaporremoval valve 55 is closed, bleed valve 57 is open, so that vacuum iscontinuously being drawn on chamber 9, although at a greater or lesserrate depending on whether valve 55 is open or closed, respectively. Itis thus assured that the pressure in chamber 9 will never exceedatmospheric, with the result that there is a minimum opportunity forsolvent vapors to escape from the system to the ambient atmosphere.

Wash motor 15 is also shown as operating throughout the cycle. Actually,wash motor 15 turns cylinder 11 at its characteristic slow speed onlyduring the first few minutes of the cycle, generally corresponding tothe wash cycle, and during the last half of the cycle generallycorresponding to reclamation for drying. Extract motor 17 spins thecylinder at relatively high speed during the intervening extract cycle,but it is easier to leave wash motor 15 running during extraction,disconnecting it by means of a clutch, than to turn it on and off,although of course wash motor 15 may, if desired be shut off during theextract cycle corresponding to the time between the four and sevenminute intervals.

As the cycle starts, therefore, vapor removal valve 55 is open, fan 107is operating and by-pass valve 39 is open. Fill valve 31 is closed, asare also dump valve 47 and vacuum break valve 51. This means that nosolvent is entering chamber 9, but that fan 107 is circulating air athigh speed through conduit and filter 106 and through the chamber whilecylinder 11 slowly turns and eductor 77 draws a fairly deep vacuum inchamber 9, as represented by the sharply descending line on FIGURE 9during the first 45 seconds or so of the first minute.

At 45 seconds, vapor removal valve 55 closes, fan 107 shuts off, by-passvalve 39 closes and fill valve 31 opens. Solvent now begins to enter andpartially fill the chamber and contact and immerse the fabric.

From 45 seconds to about a minute and three-quarters, the solventcontinues to enter chamber 9 until solvent fills about half the chamberor somewhat less. Depending upon the rate of solvent entry and thesetting of bleed valve 57, the pressure in the chamber may or may notrise from the fairly deep vacuum of 45 seconds. In the illustratedembodiment, FIGURE 3 indicates a pressure rise due to solvent enteringchamber 9 faster than vapor is bled through valve 57. In any event, at aminute and three-quarters, dump valve 47 is opened to drain the solventthrough dump conduit 45. The draining of the solvent would be very slowwere it not for the fact that at the same time, vacuum break valve 51opens to let air enter through conduit 49, so that the pressure inchamber 9 rises rapidly toward atmospheric and solvent dumps quicklythrough conduit 45 into tank 19. After about 10 seconds, vacuum breakvalve 51 closes, whereupon the draining through dump valve 47 is greatlyreduced or stopped altogether. However, fill valve 31 remains open, sothat solvent is-moving back into chamber 9 tending to replenish thatwhich was dumped when vacuum break valve 51 was briefly open. At thesame time, however, a vacuum is being drawn through bleed valve 57, andat this time, vapor is being withdrawn through bleed valve 57 at afaster rate than solvent is entering the chamber through conduit 23. Asa result, the pressure in the chamber falls off somewhat, as isindicated by the descending line immediately following the two-minuteinterval in FIGURE 3. Shortly after two minutes, the vacuum break valve51 opens again, and dump valve 47 remains open, so that even though thesolvent level rapidly falls, air rushes in still faster, which accountsfor the rise in chamber pressure between two minutes up until aboutthree minutes in FIGURE 3. At almost three minutes, the vacuum breakvalve closes and the fill valve 31 remains open, which causes thepressure to again fall because vapor is being withdrawn through bleedvalve 57 faster than solvent is entering through fill valve 31, until alow pressure is reached at about 15 seconds after three minutes, asshown in FIGURE 3. During this portion of the cycle, dump valve 47 isclosed for this final filling of the chamber. At the end of this finalfilling, fill valve 31 closes and by-pass valve 39 opens, so thatthereafter throughout the cycle the solvent will simply be recycled tothe tank 19. After this final fill, dump valve 47 and vacuum break valve51 both open, at about three minutes and 15 seconds, whereupon thepressure rapidly rises as is shown by the ascending line after the threeminute interval and up to about the four minute interval, which is theend of the wash cycle.

At four minutes, the extract motor 17 starts to operate and the cylinder11 starts to spin at relatively high velocity. It should be noted thatcylinder 11 is provided with bafiles 13, and also that the fabric withincylinder 11 is never uniformly arranged about the periphery of thecylinder. As a result, cylinder 11 presents a somewhat uneven interior,and as the cylinder with its uneven interior peripheral portion spins athigh speed, it has the ability to act as the rotor of a centrifugal fan.A very unique feature of the present invention is that the potentialityof the cylinder to act as the rotor of a centrifugal fan is utilized bywithdrawing vapor through conduit 105 from the periphery of chamber 9,circulating it through heaters 169 and 111, and return it to theinterior of 9 chamber 9 within cylinder 11. Circulation through conduit105 is thus assured by the centrifugal fan action of cylinder 11 duringextraction. At the same time, refrigeration circuit 119 is in operationand coil 125 is serving to heat heater 109, so that the vaporscirculating through conduit 105 are heated and tend to raise thetemperature of the fabric during extraction.

After extraction is partly over, heater 111 with its stem coil 113 isactuated to impart additional heat to.

the vapor circulating in conduit 105. At the same time, fan 107 isactuated to increase the circulation and also increase the heat transferto the fabric. As the fabric increases in temperature, the amount ofsolvent leaving it in vapor phase increases, so that vapor removal valve55 is also opened, whereupon the withdrawal of vaporized solvent fromchamber 9 through conduit 53 is greatly increased. These vaporswithdrawn through conduit 53 are, as mentioned above, partiallycondensed in condenser 59, then further condensed by contact with therelatively high pressure stream of liquid solvent as they enter eductor77 through the low pressure inlet, still further condensed when theremainder of the vapor emerges from outlet 85 of eductor 77 and bubblesthrough the relatively cool solvent 21, and then finally substantiallycompletely condensed as they pass out through vent conduit 99 throughcondenser 101.

Heating the fabric preparatory to reclamation of the solvent has thusbegun at the very onset of extraction and is increased toward the end ofextraction. The reclamation and extraction cycles thus overlap eachother in the present invention, and this is another example of doublingup the events of the cycle of the present invention so as to reduceoverall cycle time.

At the seven minute interval, extraction is over and cylinder 11 returnsto its previous relatively slow speed of rotation so that the damp driedfabric is tumbled in the cylinder. However, fan 107 continues tooperate, and hot solvent vapors continue to recycle at high velocitythrough conduit 105. The build-up of excessive solvent vapor in thecleaning chamber is prevented by continu ous vapor removal through valve55. Heat continues to be added to the fabric by heat exchange in heaters109 and 111. The temperature and heat content of the wet fabric israpidly rising during the first four and one-half minutes ofreclamation, up to about the 11 /2 minute interval.

At the 11 /2 minute interval, vapor recycle valve 115 closes. This meansthat the only communication between the cleaning chamber and tank 19 isnow through the inlet 31 of eductor 77. As a result, a deep vacuum isagain very swiftly drawn in chamber 9, for the apparatus is now in thesame condition as during the first 45 seconds of the cycle; however, thefabric is now damp dry and quite hot. As the pressure drops to a fairlydeep vacuum, the boiling point of the solvent rapidly falls. Theremaining solvent entirely boils off, leaving the fabric dry. Theboil-off is quite rapid, and this final drying need proceed only for ashort time. It is important, however, that prior to drawing the vacuum,the temperature of the damp dry fabric be sufiiciently high that itsheat content will be at least about as great as the heat content of thedry fabric after drawing the vacuum plus the total heat of vaporizationof the solvent at the conditions of temperature and pressure under whichvaporization occurred. In this condition, it will be remembered that thetemperature of the fabric and solvent will drop during boil-off, andthat the heat of vaporization of the solvent will in general varyinversely as the temperature. The temperature to which the fabric andsolvent drop during boil-off should of course be suificiently high thatthe solvent boils off and the fabric is left dry.

When this specification and the claims speak of the heat content of thehot damp fabric at the higher temperature and pressure being about equalto at least the heat content of the fabric plus the total heat ofvaporiza- 1 11 tion at the lower temperature and pressure, it is to beremembered that heater 111 continues in operation for a short time afterthe deep vacuum is drawn, so that heat is still added to the fabric fora short time after the deep vacuum begins to be drawn. Therefore, theterm about is to be construed with this proviso in mind.

The precise temperature conditions at the higher and' lower temperaturescannot be set forth with accuracy but must be determined having regardfor the quantity of fabric, the nature of the dry cleaning solvent, theheating equipment, and other factors well known to persons skilled inthis art. The temperature of the fabric cannot be meas ured withaccuracy and therefore cannot be set forthin this specification. Sufficeit to say, however, that the necessary quantities of heat to be added toand removed from the fabric so as to arrive at a dry fabric at the lowertemperature and pressure after drawing the deep vacuum can readily beascertained by those having ordinary skill in this art, having regardfor the vapor pressure and latent heat of vaporization curves of theparticular solvent in question and the specific heats of the fabricundergoing cleaning.

In the cycle of the present invention, therefore, the rapid boil-off ofthe solvent depends upon adding sub stantially all of the heat'necessaryto achieve that boil-off to the damp dry fabric prior to drawing thedeep vacuum. This heat addition is effected by rapid circulation of hotsolvent vapors through the tumbling fabric. The addition of solvent towhat would otherwise be hot air increases the heat content of thisrapidly recirculating vapor, and the quantity of heat to be added inthis manner can be increased as much as desired by increasing the rateof recirculation of the hot vapors. Moreover, damage to the fabric isavoided because the heat exchange between the heating elements and thefabric is indirect. The heaters are outside the chamber and are not indirect contact with the fabric. In this connection, the use of steamheat in heater 111 for the high temperature level heater is preferred,because the pressure of the steam can be so controlled that itstemperature will never rise'high enough to cause an organic cleaningsolvent to carbonize or form toxic decomposition products.

At the end of vacuum reclamation, vacuum break valve 51 opens again tolet in sufficient air to raise the pressure of the chamber toatmospheric. Fan 107 continues to operate and the cylinder continues toturn during these last 45 seconds or so of the cycle, and vapor removalvalve 55 remains open with eductor 77 operating, so that solvent vaporwithin the chamber tends to be progressively displaced and replaced byair entering the chamber through vacuum break conduit 49'at the very endof the cycle. At the same time, the fabric is aired out by the tumblingand the fan action in the presence of fresh air, so that solvent vaporsand odors are to a large extent removed from the fabric before it isremoved from the cleaning chamber.

With the return of the chamber to atmospheric pressure, the door can beopened and the dry fabric removed. The fabric will then be found to beat a temperature such that it can be handled comfortably, for therelatively high heat of the fabric just before the deep vacuum was drawnduring reclamation was reduced by the boiling away of the solvent at theend of reclamation.

From time to time, the filter powder or other finely divided solidsolvent cleaning agent on filter 25 will become spent and must bereclaimed to recover its solvent content. To do this, it is necessaryonly to open valves 35, 135, and and close valves" 29, 31, 39, and 43,with pump 27 operating, so that solvent enters filter 25 from theopposite direction and reverse washes or back Washes filter 25, so thatthe muck is stripped from filter 25 and passes through conduit 133 in aslurry and enters muck reclaimer 137 where it surrounds screen tubes14-1. Eductor 77 is operating to draw vacuum through conduit 14.3 withvalve 145 open, and the solvent is rapidly drained off through tubes 141and conduit 143 and is returned to tank 19. Thereafter, valve 135 isclosed, whereupon a relatively deep vacuum is drawn in reclaimer 137.After reclamation, the dry muck can be removed from reclaimer 137through a door (not shown).

Although the solvent in the muck does not necessarily boil duringreclamation in 137, nevertheless, the rate of evaporation of the solventfrom the muck at ambient temperature is greatly increased. Moreover,with valve 135 closed, a vacuum can be drawn in reclaimer 137 with therest of the system in operation. The evaporation of the solvent from themuck in reclaimer 137 under vacuum does not substantially affect theoperation of any other portion of the system, so that muck can betransferred to reclaimer 137 and left there to be dried under vacuumWhile the system of the present invention is otherwise in normaloperation. This is in sharp contrast to the usual muck reclaimers, whichin the first place have no such provision for convenient transfer to thereclaimer as in the present invention, and in the second place use steamor other heat to try to boil off the solvent at elevated temperature.Such elevated temperature muck reclaimers or cookers, moreover, have thegreat disadvantage that they are slow, consume a great deal of power,and require a great deal of extra equipment. The reclamation method ofthe present invention, however, obviously requires only a minimum ofadditional equipment, and is fast and inexpensive to practice.

From a consideration of the foregoing disclosure, therefore, it will beevident that all of the initially recited objects of the presentinvention have been achieved.

Although the present invention has been described and illustrated inconnection with preferred embodiments, it is to be understood thatmodifications and variations may be resorted to without departing fromthe spirit of the invention, as those skilled in this art will readilyunderstand. In particular, there are many alternative Ways of producingpressure change in the cleaning chamber during the washing cycle. In theillustrated embodiment, the pressure rises upon discharge of the solventand falls upon reintroduction of rinse solvent; but the reversearrangement can be effected, in which case the dump conduit 45 and dumpvalve 47 are made sufiiciently large that a substantial dumping flowrate of solvent can be achieved even with vacuum break valve 51 closed,so that the dumping of solvent would drop the pressure in the chamberand the refilling with solvent would again raise the pressure. These andmany other modifications and variations are considered to be within thepurview and scope of the present invention as defined by the appendedclaims.

What is claimed is:

1. A method of removing dry cleaning solvent from fabric in a chamber,comprising establishing a body of dry cleaning solvent outside a chambercontaining fabric wet with dry cleaning solvent, establishing arelatively high pressure stream of said dry cleaning solvent in liquidphase, and applying the kinetic energy of said stream to solvent vaporsfrom the interior of said chamber to force said solvent vapors beneaththe surface of and in contact with said body of solvent thereby tocondense vapors phase dry cleaning solvent.

2. A method as claimed in claim 1, and condensing from the vapor fromthe interior of said chamber solvent and water emanating from thechamber and separating the condensed water and solvent from each otherprior to introduction of the vapor into contact with said body ofsolvent.

3. A method as claimed in claim 1, and condensing from the vapor fromthe interior of said chamber solvent and water emanating from thechamber and separating the condensed water and solvent from each otherprior to application of said kinetic energy to the vapor.

4. A method as claimed in claim 1, and passing the solvent in liquidphase through a porous body of solid material to clean the solvent,removing solvent from the solid material in vapor phase, and introducingthe latter vapor-phase material beneath the surface of and in contactwith said body of solvent.

5. A method as claimed in claim 1, and passing the solvent in liquidphase through a porous body of solid material to clean the solvent, andremoving solvent from the solid material by placing the solid materialin fluid communication with the low pressure region resulting from saidapplication of kinetic energy.

6. A method of removing dry cleaning solvent from fabric, comprisingevaporating solvent from the fabric, condensing the evaporated solvent,collecting the condensed solvent in a body, establishing a refrigerationcycle in which a refrigerant is compressed and expanded in a closedfluid circuit, cooling the body of solvent by heat exchange with therefrigerant after expansion, and warming the fabric to evaporatethesolvent by heat exchange with the refrigerant after compression.

7. A method of handling dry cleaning solvent, comprising removing drycleaning solvent from fabric wet with dry cleaning solvent, collectingthe removed solvent in a body, establishing a refrigeration cycle inwhich a refrigerant is compressed and expanded in a closed fluidcircuit, cooling the body of solvent by heat exchange with therefrigerant after expansion, and warming the fabric by heat exchangewith the refrigerant after compression.

8. A method of handling cleaning liquid, comprising removing cleaningliquid from fabric wet with cleaning liquid, collecting the removedliquid in a body, establishing a refrigeration cycle in which arefrigerant is compressed and expanded in a closed fluid circuit,cooling the body of liquid by heat exchange with the refrigerant afterexpansion, and warming the fabric by heat exchange with the refrigerantafter compression.

9. A method of removing cleaning liquid from fabric, comprisingestablishing a quantity of fabric Wet with a cleaning liquid in achamber at a first pressure, heating the wet fabric to an elevated firsttemperature, and reducing the pressure on the wet fabric to a secondpressure thereby to boil off the liquid and reduce the temperature ofthe fabric to a second temperature, said first and second pressures andsaid first and second temperatures being so related that the heatcontent of the fabric and the liquid at the first temperature andpressure are at least about as great as the heat content of the fabricplus the total heat of vaporization of the liquid at the secondtemperature and pressure.

10. A method of removing dry cleaning solvent from fabric, comprisingheating the fabric to remove dry cleaning solvent from the fabric byevaporation at elevated temperature, establishing a refrigeration cyclein which a refrigerant is compressed and expanded in a closed fluidcircuit, warming the fabric by heat exchange with the refrigerant aftercompression, and cooling and condensing evaporated solvent by heatexchange with the refrigerant after expansion.

11. A method of removing dry cleaning solvent from fabric, comprisingheating the fabric to remove dry cleaning solvent from the fabric byevaporation at elevated temperature, cooling and condensing evaporatedsolvent and collecting the condensed solvent in a body, establishing arefrigeration cycle in which a refrigerant is compressed and expanded ina closed fluid circuit, warming the fabric by heat exchange with therefrigerant after compression, and cooling and condensing solvent vaporsemerging from above said body of solvent by heat exchange with therefrigerant after expansion.

12. A method of removing dry cleaning solvent from fabric in a chamber,comprising establishing a body of dry cleaning solvent outside a chambercontaining fabric wet with dry cleaning solvent and water, removingvapor from the interior of said chamber, condensing from said removedvapor solvent and water and separating the condensed water and solventand the uncondensed vapor from each other, combining said separatedsolvent with said References Cited by the Examiner UNITED STATES PATENTS1,775,699 9/1930 Silver 34-77 1,947,174 2/1934 Sando 34-77 1,960,9145/1934 McCoy -2 261-77 1,983,422 12/1934 Voorhees 122-479 10 Sando 34-77Johnson 34-77 McDonald 34-73 Cohen 34-37 Smith 34-77 Williams 34-76Severance 3477 WILLIAM J. WYE, Primary Examiner.

1. A METHOD OF REMOVING DRY CLEANING SOLVENT FROM FABRIC IN A CHAMBER,COMPRISING ESTABLISHING A BODY OF DRY CLEANING SOLVENT OUTSIDE A CHAMBERCONTAINING FABRIC WET WITH DRY CLEANING SOLVENT, ESTABLISHING ARELATIVELY HIGH PRESSURE STREAM OF SAID DRY CLEANING SOLVENT IN LIQUIDPHASE, AND APPLYING THE KINETIC ENERGY OF SAID STREAM TO SOLVENT VAPORSFROM THE INTERIOR OF SAID CHAMBER TO FORCE